1. Field of the Invention
The present invention relates to a socket structure used by connecting it to a plug of a connector attached to a nozzle of a vessel containing a fluid such as a chemical solution.
This application is based on Japanese Patent Application No. 2009-252901, the content of which is incorporated herein by reference.
2. Description of Related Art
In general, a liquid such as a semiconductor high-purity chemical or a general chemical is charged into a vessel, such as a tank, at a manufacturing plant and is shipped with a cap (lid) fitted to an opening formed in the vessel.
To take the liquid, stored in the vessel, out of the vessel, the cap is detached from the nozzle opening of the vessel, and a connector equipped with a siphon tube long enough to reach the bottom of the vessel is attached to the nozzle opening of the vessel. The connector has a plug to which the siphon tube is connected. After the attachment of the connector is completed, a socket having a liquid feed hose is attached to the plug of the connector, and the liquid in the vessel is taken out from the siphon tube through the plug, the socket, and the liquid feed hose by suction using a pump or pressure using pressurized gas.
To take the liquid out of the vessel by suction using a pump, an inert gas such as nitrogen is supplied to the vessel through a gas feed hose to compensate for a negative pressure occurring in the vessel. On the other hand, to push the liquid out of the vessel by pressure using pressurized gas, an inert gas such as nitrogen is supplied as the pressurized gas to the vessel through the gas feed hose.
Examples of structures for connecting the gas feed hose described above include a structure in which a socket for connecting the gas feed hose is attached by providing a dedicated nozzle opening in the vessel and a structure in which a gas feed hose connection port and a gas channel are formed in the socket for the liquid feed hose so that the nozzle opening is shared by the liquid and the gas.
The socket described above has a valve mechanism that opens and closes a liquid channel. A socket having a valve mechanism in the related art includes a sleeve and an inner cylinder inserted into the sleeve, with the valve mechanism disposed in the inner cylinder.
In this case, the valve mechanism includes a sliding cylinder, and the middle portion of the sliding cylinder is cylindrical bellows formed integrally with the other portion. Thus, because the bellows are formed in the middle portion of the sliding cylinder integrally with the other portion, it is possible to eliminate the labor and cost of bonding the bellows to the other portion while taking sealing performance into account and to reliably prevent leakage of, for example, liquid from the bellows over an extended period of time. For the joint between the socket and the plug, a ball lock mechanism that operates during attachment/detachment is employed (see, for example, Japanese Unexamined Patent Application, Publication No. 2000-230686).